Treatment of iron sulphide-bearing material



July ll, 1933. R. F. BACON E1' AL 1,917,229

TREATMENT OF IRON SULPHIDE BEARING MATERIAL Filed Feb. 2s, 1930 ATTORNEYS Patented duly 1l, 1933 srrss PATT. oFFlCE RAYMGND F. BACON, F BRGNXVILLE, AND ROCCO FNELLE, OF NEW ROCHELLE, NEW

YORK; SAID* FANELL ASSGNOE T0 SAID BACON' TREATMENT OF IRN SULPHDEWBEARNG iVIATERIAL Application led February 26, 130. Serial No. 431,463.

This invention relates to the recovery of sulphur and has 'for an object the provision of an improved process for recovering sulphur from heavy metal sulphide ores. More t3 particularly, the invention contemplates the provision or an innn'oved process for recovering sulphur 'from materials containing one or more sulphides ot iron. The invention further contemplates thev provision ol an improved process for treatin heavy metal sulphide ores such, for example, as ore containing sulphides of iron, copper' and nickel.

The process ot the present invention involves the treatment of ore or other metallurgical raw materials or products containing pyrites or other sulphides oi' iron, alone or in combination with sulphides of other heavy metals, such lor example, as copper and nickel, with terric chloride and sulphur chloride for the purpose of obtaining tree sulphur and/or separating iron from the mass oi. material undergoing treatment.

in carrying out a process in accordance with the present in veution, a quantity of the material to be treated is subjected to the action oi a mixture ot fierric chloride and sulphur chloride under such conditions that free sulphur and ferrie chloride are produced and vaporized. The vaporized sulphur is col lected and the ferrie chloride is utilized for treating additional quantities of sulphidebearing material to produce a product in which ferrous chloride is concentrated. The ferrous chloride concentrate is appropriately treated to regenerate the ferrie chloride and sulphur chloride. i

The chlorinating process may be conveniently conducted by passing the sulphidebearing material progressively through reaction zones of different temperatures. According to the preferred process oi the invention, the iron sulphide-bearing material is first introduced into a reaction Zone of relatively high temperature vand passed progressively V through reaction zones of lower temperatures.

The process is so controlled that ferrous chloride is produced in the high temperature reaction zones and subsequently converted to 'erric chloride in the lower temperature reaction zones. Elemental sulphur is produced and. vaporized and the ferrie chloride produced is vaporized. The vaporized sulphur and ferrie chloride are caused to pass over fresh or partially converted sulphide-bearing material in the higher temperature reaction zones, the sulphur vapor ultimately being collected as `free sulphur, and the ferrie chloride reacting with sulphide compounds and being reduced to ferrous chloride.

The chlorinating process may be carried out in any suitable type of apparatus, but it is preferably carried out in a rotary reaction chamber in which a suitable temperature gradient is maintained and into which the ferrie chloride, sulphur chloride and iron sulphide-bearing material are introduced at appropriate points.

The invention will be better yunderstood from a consideration of the accompanying flowsheet and the following description of a process involving the treatment of ore containing pyrites and sulphides of copper and nickel. s

The ore to be treated is introduced in a dry, linely divided condition into the interior of a rotary reaction chamber having charging means at one end and discharging means at the other end. An opening or passage to permit the outward passage of sulphur vapors and other gases is provided near the charging end. The temperature within the reaction chamber is so regulated that it gra-dually increases from the normal atmospheric temperature at the charging end to a `maXimum temperature of about 550O C. ata point about midway between the two ends, and gradually decreases from the zone of maximum temperature to about 300O C. at the discharge end. The opening or passage for sulphur vapors is preferably located at a point between the charging end of the chamber and the zone of maximum temperature where the temperature within the chamber is about 450 C. or slightly lower.

The ore preferably ground to provide particles sufficiently small to pass a 1GO-mesh screen in order that intimate Contact of the chlorine with the sulphide compounds may be obtained, is introduced into the reaction sit ber.

chamber at the charging end. Sulphur chloride and ferrie chloride are introduced into the reaction chamber at the discharge end.

rllhe process is conducted as a batch process, the discharge end of the chamber being closed. 'll he ore may be fed to the chamber continuously until the desired concentration has been effected, or the ore may be fed to the reaction chamber until a predetermined amount has been introduced.

When ore is hrst introduced into the reaction chamber, no sulphur chloride or ferrie chloride is introduced until the ore reaches or passes the Zone of maximum temperature. As the ore reaches the Zone of maximum temperature, the sulphur chloride and ferric chloride may be admitted, slowly at first, and in gradually increasing amounts as the orc and chlorinated material progress through the chamber. Sulphur chloride and ferrie chloride may be admitted at any desired maximum rate. rlhe rate at which sulphur chloride and ferrie chloride are admitted and the amounts admitted Will be detern'iinedv by the rate of feeding of ore into the reaction zones and the amount of ore to be treated.

During the course of the process, the sulphur chloride and ferrie chloride first react with the sulphides of iron, copper and nickel to produce free sulphur, ferrous chloride and the chlorides of copper and nickel. The free sulphur is vaporized and passes out of the reaction chamber to suitable collecting and condensing` apparatus. As the reaction chamber is rotated, the ferrous chloridebearing material moves gradually toward the discharge end and fresh ore is moved into the zone of maximum temperature. As the ferrous chloride-bearing material moves toward the disch arge end the sulphur chloride reacts with the ferrous chloride and oxidizes it to ferrie chloride. T he ferrie chloride thus produced is vapor-ized and the resulting vapor is swept along with the entering sulphur chloride and ferrie chloride toward the zone of maximum temperature. The ferrie chloride comes into contact with fresh or partially chlorinated sulphide-bearing material and reduced to ferrous chloride.

The process is so conducted and controlled that iron compounds are substantially completely eliminated from the material in the discharge end portion of the reaction chant ber and ferrous chloride is concentrated in the adjoining portion of the reaction chaim The material in the discharge end portion of the reaction chamber will consist substantially entirely of nickel and copper chlorides and gangue materials which may be present in the original ore.

'" lJVhen the orc is fed continuously during the course of a process, the admission of ore and sulphur chloride and ferrie chloride may be discontinued When the presence of considerable ferrie chloride in the issuing sulphur vapor indicates that insufficient fresh ore is being moved into the reaction Zones to react With the ferrie chloride present in the reaction chamber, or when the operations have been conducted for a predetermined length of time.

1When the ore is fed to the reaction chamber only until a predetermined amount has been admitted, the admission of sulphur chloride and ferrie chloride may be discontinued when the last portion of the ore reaches the zone of maximum temperature. The process may be so conducted that satisfactory concentration Will have been effected at that time.

ln the case of continuous feeding, at the completion of the chlorination treatment, the ironefree material containing chlorides of copper and nickel will be segregated in the discharge end portion of the chamber, fresh or substantially unaltered ore Will be present in Vthe portion of the reaction chamber between the charging end and the zone of maximum temperature, and the ferrous chloridebearing material will be concentrated in the intermediate portion of the reaction chamber.

Upon the completion of a chlorination process involving` the admission of a predetermined amount of ore, the iron-free material will be segregated in the discharge end portion of the reaction chamber, and the ferrous cl'iloride-bearing material Will be concentrated in the adjoining portion of the chamber.` rlhe charging end portion of the chamber will be empty.

When the admission of sulphur chloride and ferrie chloride has been discontinued, the discharge end of the reaction chamber may be opened. Rotation of the reaction chamber' will cause the contents to be discharged. 'lhe iron-free material containing chlorides of copper and nickel is discharged and collected first, and, While the iron-free material is being discharged, the ferrous chloride concentrate is being moved toward the discharge end. After the ironfree material has been discharged and collected, the ferrous chloride concentrate is discharged and collected separately.

llVhen the ferrous chloride concentrate has been discharged, treatment of a fresh batch of ore is commenced.

rllhe ferrous chloride concentrate is subjected to the action of air at a temperature of from about 400 C. to 800 C. in a suitable reaction chamber to recover chlorine and produce ferrie chloride. The treatment of the ferrous chloride concentrate is preferably so conducted as to produce an amount of ferrie chloride which is sufiicient for forming a suitable reagent mixture for introduction into the chlorination chamber. At elevated temperatures ferrous chloride and ferric chloride react With oxygen according to the following equations:

I. 12 FeCl2 -l- 302 Q Feg()s -l- Sllefrlls During the course of' the treatment of the ferrous chloride concentrate with air, the ferrous chloride is i'irst converted to ferrie oxide and ferrie chloride. A portion of the ferrie chloride "thus produced is then converted to ferric oXide with the liberation of chlorine. The remainder of the ferrie chloride passes out of the reaction chamber in vapor form With the liberated chlorine.

The'relative amounts of ferrie chloride and chlorine in the gases issuing from the reaction chamber may be controlled by controlling temperature and the rates of introduction of the ferrous chloride concentrate and air into the reaction chamber.

The gases containing chlorine and ferrie chloride are cooled to condense the ferrie V chloride and separatel the chlorine. The ferric chloride may be obtained in either` the l1qu1d or solid state.

The recovered chlorine together Wit i, suf-f licient fresh chlorine to compensate for losses due to leakage and the production of nickel and copper chlorides is passed through a inoltenbath of sulphur wl .'ch has been obtained by condensing a portion of the sulphur produced during the treatment of the ore with sulphur chloride and ferrie chloride. Sulphur chloride is thus produced.

The sulphur bath is maintained at a teinperature above the boiling point olV sulphurI chloride and the sulphur chloride distills ofi' as formed. The sulphur chloride vapor is collected and ma)7 be condense to eliminate inert gases. The reaction between sulphur andchlorine will proceed at a ten'iperature below the boiling point of sulphur chloride, but it is advantageous to conduct the reaction at a temperature above the boiling point of sulphur chloride in order to effect the immediate removal of the sulphur chloride from the reaction Zone. 'Condensation of the sulphur chloride Will permit the escape of inert gases which enter the system during the admission of air. lf` desired, the inert gases separated through condensation of the sulphur chloride may be conducted through a tower of solid sulphur in order to scrub out any sulphur chloride vapors contained therein.

The sulphur chloride and ferrie chloride produced are utilized for treating the fresh batch of ore.

Inert gases, such as nitrogen, which are introduced into the system during the treatment of the ferrous chloride concentrate With air may also be eliminated When the free sulphur produced is condensed.

A source of fresh chlorine is provided to compensate'for losses due to leakage and the formation of nickel and copper chlorides.

rlhe iron-free material may be treated in any suitable manner to recover 'the nickel and copper.

Vle claim: v

l; 'lhe r' cthod of treating iron sulphidebca i ll of treating' iron sulphidevlnr-,h comprises subjecting c. reaction chan'iber to the 'acrice to produce ferrous tion o. sin liloride and e ion of the chamber, subjecting the ferrous to the .ction of sulphur chloride in portirm of the chamber toY convert rric chloride, va;- contacting said rous chloride to porizingl the ic chlorine,

chlorice with the iron sulphide-bearing mate iai ;.n another portion of the chainber to produce a f ous chloride concentrate7 subjicctiiui;` the reus chloride cinicentrate to the action ol" am atan elevated temperature to producex cl'ilor ie and ferrie chloride, coinbining 'tln-wzl'ilm'nie with a portion of the sulphur produced to ,regenerate sulphur chloride, and. utilizing the sulphur chloride and ferrie chloride thus produced to treat additional iron sulphicle-hearing material.

3. '.lhe inethod of treating iron sulphidebearing material which comprises subjecting the material. in a reaction chamber' to the action of sulphur cl'aloride under such conditions that elemental sulphur is formed and vaporized and ferrous chloride is produced, subjecting the ferrous chloride to the action of air to produce chlorine an d ferrie chloride, separating the chlorine and ferrie chloride, combining the chlorine with a portionof the sulphur' p luced to regenerate sulphur chloride, and Vutilizzhig the sulphur chloride and ferrie chloride to treat additional iron sulphide-hearing material.

4r. rlhe method of treating iron sulphidehearing nlaterial which comprises subjecting he material in a reaction chamber to the action of sulphur chloride and ferrie chloride to produce ferrous chloride and eleng imiter-iai which comprises subjecting' the -nlareral in a reaction chaniber to the acmental sulphur v.infone portion et' the chamber, subjecting the ferrous chloride to the action of sulphur chloride in another portionof the chamber to convert the ferrous chloride to ferrie chloride, vaporizing the ferrie chloride, contacting said ferrie chlok ride with the iron sulphide-bearing material in another' portion oft the chamber to produce a ferrous chloride concentrate, subjecting the -ferrous chloride to the action of air at an elevated temperature to produce chlorine and ferrie chloride, combining the chlorine with a portion of the sulphur produced to regenerate sulphur chloride, and utilizing` the sul- 'phur vchloride and :torrie chloride thus produced to treat additional iron sulphide-hearing material.

5. The method ol" treating iron sulphidebearing material which comprises subjecting the material in a reaction chamber to the action oif sulphur chloride and ferrie chloride to produce elemental sulphur and -ferrous chloride, subjecting the ferrous chloride to the action of air at an elevated temperature to recover ferrie chloride and produce chlorine, combining the chlorine witha 'portion ot' the elemental sulphur produced to regenerate sulphur chloride, and utilizing the rcco'vered ferrie chloride and the regenerated sulphur chloride to treat additional iron sulphide-bearingl material.

6. The method oit treating iron sulphidebearing material which comprises passing a mixture oli chlorinating agents comprising sulphur chloride and tei-ric chloride in contact with the material and progressively increasing the ten'iperature as less chlorinated portions of the ore come in contact with chlorinating agent.

7. rllhe meth-od of treating iron sulphidebearing material which comprises passing the material and a mixture of sulphur chloride and ferrie chloride in counter-current relationship through Zones of different temperatures, said temperatures progressively increasino from the point of first contact of the mixture of sulphur chloride and ferrie chloride With the material.

8. The method of treating iron sulphidebearing material which compris-es confining the material in a reaction chamber, maintaining zones of progressively increasing tem-f peratures Within the chamber7 and introducing a mixture of chlorinating agents comprising sulphur chloride and ferrie chloride into a relatively low-temperature zone.

9. The method oi treating ore containing sulphides of iron and copper which comprises conining the ore in a reaction chamber, subjecting the ore to the action of a mixture of chlorinating Vage-nts inclu-ding sulphur chloride at an elevated temperature to form and Vaporize ferrie chloride in said chamber and obtain a substantially iron-free product containing' copper chloride, and contacting the ferrie chloride so produced With unchlorinated ore to produce a concentrate of ferrous chloride. i

10. rlhe method of treating ore containiiig pyrites and sulphides of copper and nickel Which comprises confining the ore in a reaction chamber, subjecting the ore to the action of a mixture of chlorinating agents including sulphur chloride tok term and vaporize ferrie chloride in said chamber and olot-ain a substantially iron-free product containing copper and nickel chlorides, and contacting the ferrie chloride so produced with unchlorinated ore in said chamber to produce a ferrous chloride concentrate.

ln testimony whereof We aflix our signatures.

RAYMOND F. BACON. ROCCO FANELL. 

